The projective spatial encoding techniques are widely used in medical imaging, including nuclear medicine, computed tomography (CT), and to a lesser extent, in magnetic resonance imaging (MRI). When applied to the heart, images are acquired in a time resolved manner, typically to show motion throughout the cardiac cycle. Each image frame is reconstructed from a series of projective views of the patient, with the series of projective views for that slice at that point in the cardiac cycle taken at a number of equally spaced angular positions around the body. In CT and MRI there may be 200-300 projective views per slice per time point in the cardiac cycle, and in lower-resolution nuclear medicine, there are typically 60-100 projective views per slice per time point. To acquire projective views at multiple angles at each slice and at multiple time points throughout the cardiac cycle requires that thousands of projective views per slice are required. This requirement has different implications for each imaging modality: for nuclear medicine, long scan times result, which ultimately becomes the limiting factor; for CT imaging, each projective view requires application of an x-ray source, and radiation exposure is typically the limiting factor; in MRI, scan time is typically the limiting factor. The current invention, STAR, allows time resolved image series to be generated from a reduced set of projective data, which has different implications for each imaging modality: nuclear medicine could produce images faster and with higher resolution, CT could produce images with less radiation exposure to the patient, and MRI could produce images faster.
There is an approach that uses VIPRE, which primarily works with projective data that changes in intensity with time (such as angiographic data) but which is otherwise stationary. STAR works with dynamic projective data, but there is no requirement for the data to be stationary.